The present invention relates to an electromagnetically actuatable fuel-injection valve for injection systems of internal-combustion engines, having a valve housing, a soft-iron core which is arranged within the valve housing and surrounded by a fixed magnet winding, and an armature which is arranged coaxially with and facing said core, forming a working air gap, the armature having a valve closure member which controls a valve outlet as well as lower and upper guide surfaces by which it is guided in the valve housing, the lower guide surface being arranged close to the valve closure member.
Such injection valves are presently used in automobile engines and are therefore generally known.
In the known fuel-injection valve, the armature is guided via its two guide surfaces in a nozzle body and thus relatively far from the magnet winding. The nozzle body itself is guided in sealing fashion in an inner bore in the valve housing. Above the upper guide surface of the armature, the armature has considerable play on all sides with respect to the valve housing so that the armature cannot jam.
In the known injection valve, the magnetic flux between valve housing and the armature must take place, over a relatively large air gap below the magnet winding and in part far away from the magnet winding, from the valve housing via a guide to the nozzle body and from there via another guide to the armature. Due to this there are losses in magnetic flux which must be taken into consideration when dimensioning the magnet winding and the armature. In order to obtain a fuel-injection valve which has as little inertia as possible and is therefore rapid-acting, it is, however, desirable to use an armature which is as low in weight as possible.